Wash lentils well. Put drained lentils into saucepan with all the main ingredients except thick milk and salt (green chillies, turmeric, red onion, curry leaves and thin milk). Bring to the boil, then cover and cook slowly until the lentils are soft.

Heat oil in a frying pan, and add the ingredients for tempering. When the onions are golden in colour add to the lentil mixture.

Add the thick milk and salt to taste. Simmer uncovered until the gravy is thick.